Retrolental-Fibroplasia (RLF) is a disease of prematurity which is still occurring in spite of close monitoring of PaO2 tensions and restriction of oxygen (O2) therapy to that necessary for survival. Though of lesser severity than that which occurred when oxygen was being used indiscriminantly and without monitoring of arterial oxygen tensions, the RLF occurring today is nevertheless associated with serious sequelae such as myopia, anisometropia, strabismus, amblyopia, pseudo-exotropia, peripheral retinal degeneration, vitreous and retinal detachments and retinal tears. Deficiency of Vitamin E is also a disease of prematurity. In 1971, 80% of infants with birth weights below 1500 gm, who were fed standard nursery formulas, often containing added iron, showed clinical evidence of hemolytic anemia caused by this deficiency state. Vitamin E plays a central role in the body's defenses against obliterative damage. It has, in the past, been found to decrease the severity, but not the overall incidence, of RLF under conditions of uncontrolled O2 therapy. The effect or treatment with Vitamin E under conditions of controlled O2 therapy has not been tested. This proposed study will assess the influence of early treatment with parenteral Vitamin E on the incidence, severity and long-term sequelae among infants whose oxygen therapy is carefully monitored and who receive no supplemental iron during the period of retinal vascular immaturity. This will be done by means of a controlled clinical trial using a parenteral preparation of alpha-tocopherol acetate which is being supplied by Hoffman-LaRoche, Inc. Preliminary data from the pilot study now in progress strongly suggests that treatment with Vitamin E decreases the visual morbidity of prematurity by its effect on RLF.